• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Starting problem

Dogface

New member
I'm new to Beemers in general and certainly Airheads. Just bought a really nice R75/5 but I'm darned if I can get it started easily. It usually takes me ten + minutes of trying to get it to roughly kick over. Once started it idles way too low so that may be part of the problem. Does not seem to matter what degree of choke I use or how much/little throttle...it just don't wanna start.

There is only one Beemer dealer in Sac and they don't wanna work on these old bikes.. My small town an hour north is devoid of shops that know these bike.

Please gimme some suggestions :banghead
 
I'm new to Beemers in general and certainly Airheads. Just bought a really nice R75/5 but I'm darned if I can get it started easily. It usually takes me ten + minutes of trying to get it to roughly kick over. Once started it idles way too low so that may be part of the problem. Does not seem to matter what degree of choke I use or how much/little throttle...it just don't wanna start.

There is only one Beemer dealer in Sac and they don't wanna work on these old bikes.. My small town an hour north is devoid of shops that know these bike.

Please gimme some suggestions :banghead

.........tight valves.

Check the clearences and adjust as necessary before any carb adjustments.
 
It could be as simple as your starting technique...each bike will need something a little different in order to get it to catch. Start with the basics...choke on (more on that later), hit starter button, and generally don't open the throttle as this tends to lean things out. Once started you should stay on choke and probably ride off at a slow speed within 30-60 seconds. Maybe a minute later, go to half choke and then another minute after that, choke off. On my /7, I find I need to crack the throttle a small amount during the cranking process...

You could have a carb problem, like the chokes really aren't working and then you have an idle issue once started. This sounds like you really need to go through the carbs and clean everything and install new seals, focusing on the choke section. If you omit replacing the throttle shaft o-rings, the process is fairly straightforward and Bing or any of the on-line parts places will have the parts. After rebuilding the carbs, you'll need to perform a carb synch to get the mixture, idle, and throttle cable tension set properly. This has all been discussed on this forum. Also, Bob Fleischer aka Snowbum has a website that will give you particulars about this. There was a recent post about synching carbs.

You could have electrical issues from weak spark (plugs, wires, coils) or your timing could be off. Your advance unit might not be functioning properly and not giving you the proper advance from idle up to 3K RPM. Make sure your battery is fully charged to get the motor spinning as faster as it can.

Oh yeah, like Rich says, sometimes carb problems are really the valves!!

You could also check with Ted Porter at http://www.beemershop.com in NorCal to use his services, buy parts, or get advice.
 
Simple is a good idea;

Do not ever forget the "Keep it Simple Stupid" quote of many, many years from many old, older Airhead riders before us. I like the quote and have found it so strikingly accurate, when trying to diagnose an airhead. Its more often than not, the simplest fix that gets it running again! Almost 40 years on beeemrs for me now and if you want a great statement to always remember about these older twins, its this one:). Dealers not wanting to work on Airheads? Dumb,dumb and dumber is all I can say. Quite often, its easy money for a dealer and his wrench with some time under their belt! A dealership not working on older beemers is a dealer with limited educated staff in the shop, period! I don't want 'em near my bike. Yep, I say and agree the "valves" are most probable to look at first and a simple proceedure indeed. Just learn the flywheel mark "OT" and you're in like flynn. Its the mark for valve adjust, top center, then 180 degrees on the crank for the other side. Done:). Set 'em at 6 and 8 thousanths, the larger 8 for exhaust valve. Happy Trails, Randy13233 PS; even bad carbs start a bike usually and his description of nothing happening, leans hard on a valve adjust or electrical issue. :usa
 
I have a R65 (1983) and it is even more stubborn than yours. I even installed a heavy guage "pigtail" to the B+ so I can use a portable battery after the regular battery goes dead.

I find it starts easily in warm weather and hates cold weather.Try starting the machine, walk away and come back 15 minutes later. Then it starts.

They seem to have an airhead mind of their own.

But ...


Once they get running - a ride experience like no other.

Try joining the Airheads and find local airhead riders.

In the meantime if you want to commiserate ... <- Check Out This Link
 
Last edited:
Be sure to check your plugs and wires. The plugs need to be changed fairly often in these bikes and the older wires can have far too much resistance. Both will cause hard starting.

Plugs are cheap and easy to change. You can get wires for less than $30 in several places.

If the plugs are fouled, you may get an immediate improvement in your starting, but it won't last unless you correct the problem that is causing the fouling.

Best of luck.

By the way, I love the combination of your user name and avatar picture. Grizzly bear meets teddy bear.:clap Classic.
 
Just learn the flywheel mark "OT" and you're in like flynn. Its the mark for valve adjust, top center, then 180 degrees on the crank for the other side. Done:). Set 'em at 6 and 8 thousanths, the larger 8 for exhaust valve.

Randy -

I know you are aware of this, but I just wanted to add to what you said... Be sure the side you're adjusting the valves on is at "OT" on the compression stroke. Secondly, it should be turn the crankshaft 360 degrees to set the other side. Rotating the engine 360 degrees puts the other side at "OT" on the compression stroked.
 
+1 on the valves. Correct valve clearance adjustment and correct point gap are the necessary settings to achieve before moving on to other parameters. My experience with the /5's over the last 20 years or so is it that hard starting is points and non-idling is valves. Both factors normally work in combination to make a bike hard to start and run poorly. If you are not experienced with breaker point ignitions, you will find it difficult to deal with the point set where it resides under the front cover. The mechanical advance obstructs access to the point set.
Also, NEVER REMOVE THE FRONT COVER WITHOUT FIRST DIS-CONNECTING THE BATTERY NEGATIVE TERMINAL. Good luck and don't get discouraged. I am willing to answer any questions you have either on this forum or in Private Messages thru this forum, or over the telephone.
 
kissx2

just a thought. assuming your choke lever is on the side of the engine as mine is, I noticed recently that ocassionally I wasn't quite fully opening it. The lever hung up about a 1/4 to 1/8'' from fully pushed and needed a definite extra little bit of oomph. Just that last little bit made all the diff btw starting immediately, and a really frustrating fifteen minutes. I hope your solution turns out to be as simple as mine was.

I just re-read the nice Tom Cutter article about dual-plugging and it reminds us that opening the throttle defeats the choke. He advises not to turn the throttle till just after it turns over.

Hope it helps.
 
If you want to take it to a BMW shop go to Ozzie,s

Ozzie's BMW Center
2438 Cohasset Road
Chico, CA 95926
phone: (530)345-4462
 
Back
Top